In general, cephalosporin compounds are poor in absorption from digestive tract, and therefore, are usually administered by injection. For example, there have been known cephalosporin compounds which have a wide range of excellent antimicrobial activities and are represented by the following formula (A) ##STR2## wherein R.sup.1 is hydrogen atom or lower alkyl, and salts thereof [hereinafter the compounds encompassed in formula (A) including known compounds are referred to as Compound (A)]. However, said Compound (A) is also poor in absorption from digestive tract, rendering administration by injections inevitable.
Although various attempts to introduce a liposoluble ester residue into the 4-position carboxylic acid of Compound (A) to improve absorption from the digestive tract, and to produce compounds capable of converting into Compound (A) by decomposition upon absorption into blood are currently in progress, such compounds are all unsatisfactory since they permit no improvement in absorption from the digestive tract and show inconsistent absorption due to their poor solubility in water. In addition, the compounds obtained as a result of such attempts are generally poor in taste, particularly bitter, making formulation of pharmaceutical preparations easily taken very difficult.